The invention relates to a stench trap for a urinal, having an interchangeable pot for insertion in the urinal and a cover for covering the pot. The cover has an opening for introducing urine into the pot, a baffle projecting into the pot for restraining sewer stench from the outlet connection, and a stench trap floating on the urine intended to accumulate in the pot.
From the prior art urinals are known, which must be flushed with water following each use. Due to the reduction of the amount of flushing water as a consequence of higher water prices and/or smaller amounts of water being available, such urinals require a disproportionate cleansing expenditure. Due to the mixture of urine with water, the formation of urine stones is promoted, and not only parts of the urinal, but also in particular the siphon-bearing discharge pipes leading away from this, are reduced in cross section by formation of urine stones within a few months and must consequently be cleansed. In addition to the high costs for the required flushing water, there arc those for the periodic cleansing/repair of the pipes.
For these reasons, waterless urinals have already been proposed. From German published patent application DE-A1 28 16 597 (Ernst), a pot-shaped insert is known, which is inserted into a recess located at the deepest point of the urinal and is connected with the outlet pipe. In the insert an annular space is formed, in which a cylindrical jacket-shaped tube is inserted from above, which subdivides the annular space into two regions, an inner and an outer, which are connected with each other and form a stench barrier or a siphon. A barrier liquid of lower density than water, for example oil, is present in the outer annular space. The urine entering into the container passes through the barrier liquid due to its higher specific gravity and thus reaches the outlet and from there the sewer system. This device has the disadvantage that the barrier liquid, which can contain additional active disinfecting agents and optionally fragrant substances, is successively flushed away by the strong stream of water passing through the barrier liquid during the periodic cleansing of the urinal with a strong torrent of water and consequently loses its action.
In International Patent Application publication WO 97/15735, an insert for a waterless urinal with a barrier liquid is disclosed which, through the special geometrical construction of the insert container, should prevent the barrier liquid from floating away. Even if the floating away of the barrier liquid is substantially prevented there, it cannot be avoided, however, that its active ingredients, which are necessary to create a flawless protection against stench, are successively degraded, and consequently even with this arrangement, the barrier liquid must frequently be replaced. Also, the substances which are used for the barrier liquid are not completely harmless, and can lead to problems with wastewater processing. Monitoring the momentary condition of the barrier liquid can create additional difficulties, since this is not directly examinable, and in principle, only the nose decides whether enough of it is present, or whether this has already been degraded or indeed flushed away.